Aero gas turbine engines such as aero turbofan engines have developed to a high technological level during the past 70 years. However, since atmospheric density and oxygen decrease with the increase of flight altitudes, engine thrusts using air as an oxidant are decreased, and thus an aircraft cannot fly too high and too fast. Airliners usually cruise at an altitude of 10 km and at a speed of nearly Mach 1. Military aircrafts can fly higher at supersonic speed; however the increase of Mach number and the flight altitude is limited.
Liquid rocket engines that can work at any altitudes also have a high technological level after over 70 years of developments. Some liquid rocket engines are used for propelling rocket aircrafts over a flight altitude of 20 km and above a speed of Mach 2, for example, American AR2-3 rocket engine. However, such engine requires a consumption of much more hydrogen peroxide having a concentration of 90% as oxidant than aviation kerosene. Such engine is not economical, and the flight speed, altitude and duration are limited due to the heavy-load oxidant.
The inventor has studied an engine that makes full use of oxygen in the atmosphere for combustion and works at various altitudes, and filed a Chinese Patent No. CN 105841193B, titled “Two Aerospace Turbofan Engines”. An International Patent Application No. PCT/CN2016/000335 which claims priority from the Chinese Patent No. CN 105841193B has been filed and published on Nov. 23, 2017 (WO 2017/197544 A1).